SS303 Yield Strength 1

[Cschell]

'am looking for Yield Strength data for 303 SS at Room Temp. The catalog for the 6.00mm shafting stock lists the Hardness at RB75 to RB95 for the DIN 1.4305 material. The Yield Strength is probably in the range of 35-45 ksi, but I would like to get more specific data, say Syt vs Hardness -- maybe also with a characterization of Condition of the material. TIA
C. Schell, Sr. ME
Lasentec, A Mettler Toledo Co.

 

[mcguire]

You won't be able to get more precise information unless it is on a specific lot of the material. The yield strength will depend on the chermical composition of the batch of steel in question and its thermo-mechanical history. Even then the tensile data on that exact lot of steel will have one standard deviation of 500 to 1000psi.

 

[Cschell]

Thanks, mcguire!
I realize that there is a lot of variability in the Syt values, even if one is able to characterize the material more fully -- say, as &quot;Half-hard 303SS 1/4&quot; rod stock&quot;, or even with a measured hardness value -- and that the only thing close to a &quot;sure thing&quot; is to do a tensile test on the specific lot of material to be used. Otherwise, it is somewhat akin to &quot;nailing Jello to a wall&quot; <g>
This said, however, I would still like to find some 303SS Yield Strength data (mean value, though min/max would also be nice)as a function of Hardness -- with whatever other qualifiers might apply (such as size/type of rod stock, and/or coldwork/process history, etc.) I have managed to find some such info at the MatWeb site (

http://www.matls.com),

for example. Anything else that you could point-me-to would be appreciated. Thanks again for your response. C. Schell, Sr. ME
Lasentec, A Mettler Toledo Co.

 

[mcguire]

I have some data on the test lab statistics from a stainless steel mill I worked at. The results from MANY tests were yield strength 42,628 psi, standard deviation 3698 psi hardness Rb 83, standard deviation 3 points.
This won't let you correlate YS to hardness, nor should it.
Yield strength varies with grain size,cold work, and carbon/nitrogen level. Hardness does vary with cold work in the same way as yield strength, but inversly with carbon/nitrogen and hardly at all with grain size. Yield strength is subject to a lot of testing variables in specimen preparation and pulling.
If you're looking to manage hardness, yield strength, or their ratio things can be done, but measuring them has some inherent noisiness.

 

[Cschell]

Thanks, again, McGuire!

'sorry for the delay in responding. I appreciate the additional information that you provided. Having worked in a stainless steel mill, you must have acquired a lot of valuable knowledge concerning these alloys.

I can appreciate the complexities in the relationships between YS, and Hardness, %Cold Work, and other parameters that you mention. I'm just a bit &quot;frustrated&quot; that when I purchase 303SS &quot;Shaft stock&quot; from someone like W.M. Berg I am left nearly &quot;clueless&quot; as to the state of the material -- though I suspect this rod stock is in a fairly &quot;soft&quot; condition (annealed to say 7%CW?). I cannot get any thermo-mechanical history on the material. The broad Hardness spec given in the catalog (RB75 to RB95) is fairly useless in defining the material for engineering calculations. In fact, RB75 appears to be very low for 303SS; I find that annealed 303SS is more like RB83. I suppose one must buy special order rod stock to achieve any level of certainty about its yield point, etc.

Would you know if the 303SS &quot;Shafting stock&quot; that is typically sold is, in fact, in an Annealed state? -- or if some of it is still in a cold-worked, &quot;Hard-drawn Rod&quot; condition? Much of the &quot;Shafting stock&quot; in the 4xx alloys are deliberately hardened (even induction or case hardened), thereby providing much higher hardnesses and yield points. FYI, my original question stemmed from a desire to estimate the onset of yield in a &quot;beam&quot; of this 303SS shaft material. I was, frankly, surprised to find that W.M. Berg could tell me NOTHING about the condition of their 303SS &quot;Shafting stock&quot; (beyond the Hardness spec in the catalog)! Even if one tensile tests a given lot of the material, there is no guarantee that the next lot will be at all similar. So, I suppose it's &quot;par for the course&quot;!

Thanks much for all your comments/suggestions, McGuire!
C. Schell, Sr. ME
Lasentec, A Mettler Toledo Co.

 

[mcguire]

I'm appalled that a distributor says it can't furnish more information than that! Every producing mill keeps identity of each lot it sells and the tested properties of that lot. Every good mill can also relate to that lot number the specific processing parameters. Sounds like you should talk to your purchasing agent about a new supplier. If Berg can't help, you should be able to contact the mill that made the steel and get your information. The only uncertified material is secondary quality.

 

[Cschell]

Hi, McGuire!

'just got your quick response, and wanted to thank you again. I agree completely with your comments! I have almost always found suppliers willing to provide material information. So I was not only apalled by W.M. Berg's total inability, or reluctance, to provide such information on their shafting stock, and their reluctance to reveal their source (a grinding shop), but was really taken-aback when they refused to even RELAY the information between me and the source! Therefore, a new supplier of this precision-ground rod stock seems to be in order! I appreciate your responses very much! Have a nice day!
C. Schell, Sr. ME
Lasentec, A Mettler Toledo Co.